1. Field of the Invention
The present invention relates generally to a device for forming plastic balls from a bar of plastic material, and it also relates to a device for forming a ball of plastic material consisting of filler material, such as bean jam, fruit jam, cream, minced meat, chopped vegetables or other materials, encased in an envelope of plastic covering material, such as bread dough, rice dough or other malleable or plastic materials, from a bar formed of a sleeve consisting of a covering material surrounding a central core consisting of a filler material.
Particularly, the present invention concerns a device comprising a pair of identical circular cutters each having an improved cutting member on the peripheral side surface between the top and bottom planar surfaces thereof.
2. Description of the Prior Art
The device hitherto used for formation of the above-mentioned balls is disclosed, for instance, in U.S. Pat. No. 3,351,026, and comprises a pair of identical circular cutters, each with top and bottom planar surfaces and a peripheral side surface, which cutters are rotatable about their respective axes disposed vertically and parallel to each other. The cutters are arranged on the same level, with a predetermined gap therebetween, and each cutter is formed on the peripheral side surface thereof with a cutting member which consists of a single spiral blade extending along the peripheral side surface of the cutter such that the spiral blade starts at the upper end of the said peripheral side surface and terminates near the lower end thereof substantially under the starting point of the blade. The edge of the blade is blunted throughout its length and the radius of a surface of revolution formed by the edge of the blade about the vertical axis of the cutter increases gradually from the top to the bottom. The cutters are rotated at the same speed and in the same direction so that the cutting blades meeting in opposition to each other at the said gap are always at the same elevation.
A bar of plastic material is continuously supplied downwardly toward and into the gap between the rotating cutters, and is separated by the cutters to produce one ball after another in succession in such a way that one ball can be obtained for every one revolution of the cutters. It is preferable that the central axis of the bar supplied to the cutters coincides with the vertical line passing through the middle of the said gap.